A wildfire that has consumed parts of Yosemite National Park and charred an area greater than the city of Dallas, Texas, is expected to intensify on Friday and is now California's third largest wildfire on record, fire managers said.
The 20-day Rim Fire, named for the popular Rim of the World looking, is expected to burn another two weeks, they added.
The blaze has blackened about 246,350 acres (99,694 hectares), or 385 square miles, of timber and chaparral in the rugged northern California forests since it broke out on Aug. 17.
Fanned by wind in hot and dry weather, the fire has grown by almost 10,000 acres since Thursday, although it has stayed mostly within containment lines that firefighters have drawn around 80 percent of the blaze's permimeter.
"Fire activity is expected to intensify Friday as unburned areas within control lines are consumed on the Rim Fire," the California Department of Forestry and Fire Protection, the U.S. Forest Service, and other agencies said in a joint statement.
Hot, dry weather and strong winds are expected throughout the weekend, and would challenge further containment line building, they said.
The Rim Fire ranks as the largest of dozens of wildfires that have raged across several states in the drought-parched West this year, straining U.S. firefighting resources.
The fire was started by a hunter's illegal campfire that got out of control in secluded Stanislaus National Forest, officials said on Thursday.
Friday's setback follows efforts by ground crews on Thursday to tame the fire using hand tools and chainsaws, backed by bulldozers, water-dropping helicopters and airplane tankers with payloads of chemical retardant.
A stretch of Highway 120 that leads from Groveland to the west side of the 750,000-acre (300,000-hectare) park was set to reopen at noon on Friday.
Yosemite has some 4 million visitors each year, mostly from June through August. About 620,000 normally visit in August alone, but the fire has caused tourism at the park to decline.
Firefighting costs had run $84.8 million as of Friday, with some 5,000 personnel assigned to battle the blaze at its peak, though crew numbers have dropped to roughly 3,600.
Officials said 111 structures, including 11 homes, have been destroyed, and roughly 1,900 structures in the region were still threatened by the blaze on Friday.
But no serious injuries have been reported, and most evacuation orders and advisories have been lifted as firefighters tightened their grip on the flames.